A seafood vendor solicits customers in Beijing's Sanyuanli Market in February. Photo: Li Hao/GT

Seafood-loving Chinese are conditioning themselves off frozen food, industry insiders said, after a top Chinese epidemic expert stressed on Friday that the coronavirus is cold resistant and can live up to two decades at low temperatures.

Top Chinese epidemiologist Li Lanjuan said the coronavirus is particularly cold-resistant and can survive for months at -4 C and 20 years at -20 C, which explains why the virus has been found several times in seafood markets, and the virus can be transported across borders, the China News Service reported on Friday.

The comments come after a sudden coronavirus outbreak hit Beijing, and media reports that the virus was detected at slaughterhouses in the US and the UK, and on the heels of new findings by the top Chinese epidemic control agency on the nature and origin of the Xinfadi outbreak.

It is likely that the virus strain found at the Xinfadi market has come from Europe, but it is older than Europe's most recent strain, said Chinese health officials, citing preliminary research results from recent samples.

Alarmingly, according to a report posted on the website of the Communist Party of China Central Commission for Discipline Inspection on Friday, more than 200 samples from the underground seafood market were initially collected, including a salmon throat swab, and many of the samples have tested positive for the virus.

Previously, media reported the virus had been found on a chopping board for imported salmon in the Xinfadi market. Subsequently, sales of fresh salmon in the city and beyond have been suspended.

China's General Administration of Customs said to address people's concerns on imported frozen food, it took a total of 15,638 samples across China from high-risk countries and regions on Thursday, including 3,508 samples from goods and 10,608 samples from packaging, and all tests were negative. Before that, all tests taken since February were also negative. 

Still, an epidemic control expert from Beijing on Friday suggested that people abstain from and properly disposing of frozen seafood, soy products and other food purchased at Beijing's Xinfadi market to avoid being infected by the coronavirus.

Li Guoxiang, an expert with the Chinese Academy of Social Sciences, said the recent development has clearly shown that the virus can exist in low temperatures for a very long time and can somehow find its way into cold-chain logistics.

"The latest outbreak shows this adaptable virus has gotten a step ahead of our inspection and quarantine deployment," Li told the Global Times on Friday.

"Scientific and medical knowledge of the virus has been updated by the days, and our quarantine measures will have to be ramped up to keep abreast of the rapid changes in this pandemic," Li said.

Quarantine officers at Chinese ports and borders are routinely updated with checklists for the pathogens, residues, toxic and hazardous materials they have to monitor. 

Li expected that after the sudden resurgence of the virus in Beijing, inspection and quarantine at imports will be strengthened to the maximum level with a long-term mechanism to follow in the future. "Attention now will be equally on the flow of trade and the flow of people."

Fear of the contagion can already be felt across China, even outside Beijing.

"We have a sense that our customers are psychologically cordoning themselves off from freezing foods for the moment," an employee from the PR department of the Port of Guangzhou told the Global Times on Friday.

Customs and quarantine officials on June 13 conducted an inspection of the various seafood markets at the port, the world's fifth largest, and obtained 71 samples. All samples tested negative.

On-site hygiene and license verification checks followed and health checks for shopkeepers and operators have all been beefed up at the port, the PR employee said.

A research note from Sealand Securities this week pointed out that while the source of this second outbreak has yet to be identified, the market has come to the realization that imported aquatic products, freezing or frozen foods carry risks of spreading the virus, and negative impacts will be felt by imported seafood and aquatic products. 

The news is positive for domestic meat producers, the brokerage said. The report also raised the possibility of a domestic substitution for imported aquatic products, though experts said China could not replace all produce from overseas markets.

The Norwegian Food Safety Authority in an interview with the Global Times on Thursday vehemently denied the theory that salmon could be a host or intermediate host of the virus, citing current knowledge. 

But the Norwegian agency said exports of fresh whole salmon last week from Norway to China dropped 34 percent year-on-year to 240 tons.

Ministry of Commerce spokesperson Gao Feng was unimpressed by the notion that China may opt for an across-the-board-style ban of foreign imports of seafood and meat.

Gao said at a press conference on Thursday that increasing imports of food and agricultural products is an important component of China's proactive import policy, but he emphasized the need to strengthen communication and coordination with relevant countries to secure the quality of imported foods and agricultural products from the source.

Customs officials at the Port of Tianjin have already implemented a carpet-style inspection of all imported frozen and freezing meat, fish and other seafood from June 14, according to media reports.